Pneum atic tool



July 30, 1963 M. D. HozA 3,099,187

PNEUMATIC TOOL Filed Feb. 20, 1961 2 Sheets-Sheet 1 Maf 2//7 /L/oza INVENTOR.

July 3o, 1963 M. D. HozA 3,099,187

PNEUMATIC TOOL Filed Feb. 20, 1961 2 Sheets-Sheet 2 /Wa/ f//7 H020 INVENTOR.

United States. Patent O 3,099,187 PNEUMATIC TOL Martin D. Hoza, Houston, Tex., assignor to Reed Roller Bit Company, Houston, Tex., a corporation of Texas Filed Feb. 20, 1961, Ser. No. 90,395 6 Claims. (Cl. 91-232) This invention relates generally to pneumatic tools and more particularly .to cylinder heads for percussive too s.

An object of this invention is to provide a new and improved pneumaitc tool useful for removing paint, rust and scale from surfaces.

Another object is to provi-de a new and improved removable cylinder head yfor a pneumatic tool.

Another object is to provide a new and improved means for securing a cylinder head lto the body of a pneumatic tool.

Another object is to provide a pneumatic tool structure which is economical to manufacture and easy to service and maintain.

Another object is to provide a resilient cylinder head for a percussive tool.

Other objects will become apparent from the following description and accompanying drawings, in which:

FIG. l is la side elevational view, partly in section, of an elastic pressure uid operated, multiple piston tool embodying the invention.

FIG. 2 is -a sectional View taken along line 2 2 in FIG. 1.

FIG. 3 is a sectional View taken along line 3 3 in FIG. l.

FIG. 4 is la `:sectional view taken along line 4 4 in FIG. 2.

Referring to the drawings, a multiple piston scaling tool is shown generally at 1 comprising an aluminum alloy body 2 having a plurality of cylinders 3. The cylinder 3 has a larger bore 4 and a smaller bore v5. A steel piston 6 is `disposed in each of said cylinders 3. The upper end of the piston 6 iits within the larger bore 4 and the lower end of the piston 6 iits within the smaller bore 5. The lower portion of `the piston 6 terminates in an end 7 which is adapted to do work on a surface.

A resilient, or plastic, cylinder head 8 which may be made of synthetic rubber, or other suitable plastic material, is secured in the upper end of the cylinder 3. The cylinder head S may have a diameter which is slightly larger than the diameter of the bore 4 so that it may be pressed into the bore 4 to seal the upper end of the cylinder 3. The cylinder heads 8 have holes 9 transversely therethrough, and the body 2 has holes 10 extending therethrough and registering with the holes 9 of the cylinder heads y8 as shown in FIG. l. A securingpin 11 having a diameter slightly larger than the diameter of the lholes 9 is inserted through the holes 10 of the body 2 and the holes 9 of the cylinder heads 8 to secure the cylinder heads S within the cylinders 3. Since the cylinder heads 8 are made of resilient material and the holes 9 are smaller in `diameter than the diameter of the pin 11, the pin 11 is held axially in place Iby friction.

A hollow handle 12 is threadedly secured in the inlet 13 of the body 2. The other end of the handle 12 may be attached to a valve 14 which communicates with a suitable source of motive power such as compressed air. The body 2 has an alternate inlet 15 which is sealed by a plug 16. If desired, the handle 12 may be secured in the inlet 15 whereupon the plug 16 would then be used to seal the inlet 13. The head 2 has an air inlet passageway 17, one end of which may be sealed by plug 18. The inlet passageway 17 communicates with .the inlet 13 through port 19.

In operation, an elastic pressure fluid, usually com- 3,099,187, Patented July 30, 1963 lCe pressed air, is admitted through the valve 14 and hollow handle 12 into the inlet 13, through the port 19 and into the inlet passageway 17 which communicates with the lower portions 20 of .the cylinders 3. The liuid pressure in the portion 20 is maintained close to operating pressure so long as the valve 14 is open. The portions 20 communicate with live air ports 21. The exhaust port 22 communicates with exhaust 23and the port 21 serves to admit high pressure fluid to the uppervvsurface 24 of the piston 6. As shown in FIG. 2, when the exhaust port 22 is closed Iby the piston 6, the live air port 21 is open thus admitting high pressure Huid to the surface 24 of the piston 6. The shoulder 25 of the piston 6 is also exposed to the same air pressure. Since the piston 6 has a larger .area at 24 than the area of the shoulder 25, the piston 6 will then move down to a position shown by the dotted lines as indicated 4at 6. As the piston 6 moves down, the exhaust port 22 is opened and the live air port 21 is closed allowing the fluid pressure acting on the piston surface 24 to drop to zero. The pressure acting on the area of the shoulder -25.then moves the piston 6 to the up position, closing the exhaust port 22 and again opening the llive air port 21 to admit high pressure fluid to the surface 24 of the piston 6 for the next cycle. Y

As the piston `6 reciprocates within the cylinder 3, it may come into cont-act with the cylinder head 8. Since the cylinder heads -S are made of a resilient or lplastic material, they serve to cushion the impact of the piston 6 whereupon the battering effect of such impacts on the pistons -6 and the walls of the cylinders 3 is alleviated. It will be apparent that the cylinder heads 8 may be easily removed in order to change the pistons 6 or to service the to'ol. The cylinder heads 8 being frictionally secured within the cylinder 3 and upon the securing pin y11 are not easily vibrateid loose. The cylinder heads yS may be molded or otherwise formed, thus providing a relatively inexpensive cylinder head which does not require close manufacturing tolerances to effect a duid-tight seai for the upper end of the cylinder 3. Actual operations indicate that the tool of the invention provides longer useful tool life, and is easily serviced for maintenance or to 'replace the pistons 6.

The invention is not limited tothe embodiment shown. Various changes within the Iscope of the following claims wild occur to those skilled in the art.

I claim:

1. An elastic pressure fluid operated percussive tool comprising a body having :a plurality `of cylinders, each cylinder having a bore of two diameters, Ia piston in each of said bores having an upper portion tting the larger portion of said bore and a lower portion fitting the smaller portion of said bore and extending therethrough outwardly from said body and terminating in an end adapte-d to work on a surface, the said y.body having passages controlled by said piston for admitting `and exhausting pressure fluid to cause the pistons to reciprocate within said cylinders, la synthetic rubber cyl-inder head in the upper end of each of said larger bore portions to seal the same, each lof said resilient cylinder heads having a hole transversely therethrough, the said body having holes therethrough registering with said cylinder head holes, a single pin extending through said holes in said body and cylinder heads, the said pin having a diameter l-arger than the diameter of said cylinder head holes.

2. A uid operated percussive tool comp-rising a body having a plurality of cylinders, each cylinder having a -bore of two diameters, a piston in each of said bores having an upper portion iitting the larger portion of saidy bore and a lower portion iitting the smaller portion of said bore and extending therethrough outwardly from said body and terminating in an end :adapted to work on a surface, the said body having passages controlled by said piston for admitting pressure uid to cause the pistons to reciprocate within said cylinders, a plastic cylinder head in the upper end of each of said larger bore portions to seal the same, each of said resilient cylinder heads having a hole transversely therethrough, Athe said ibody'having holes therethrough registering with said cylinder head holes, 'la single pin extending through said holes in said body and cylinder heads, the said pin having a diameter larger than the vdianteterof said cylinder head holes.

3. A uid operated tool comprising a body having a cylinder, said cylinder having a bore of two diameters, a piston in said bore having an upper portion iitting the larger portion lof said bore and a lower portion iitting the smaller portion of'said bor-e and extending therethrough outwardly trom said body and terminating -in an endadapted to work on a surface, the said body having passages controlled by said piston for admitting and exhausting pressure iiuid to cause the piston to reciprocate within said cylinden a resilient cylinder head in the upper end of said larger bore portion to seal the saine, said resilient cylinder head having a hole transversely therethrough, the said body having holes ltherethrough registering With said cylinder head hole, a pin extending through said holes in said body and cylinder head, the said pin having :a diameter larger than the diameter of said cylinder head hole.

4. A duid operated tool comprising -a body having a cylinder, said cylinder having a bore fof two diameters, a

piston in said bore having an upper portion fitting the larger portion of said bore and a lower portion tting the smaller portion of said bore and extending therethrough outwardly from said body and terminating in an end adapted to work on la surface, the said body having passages con- 4 trolled by said piston for admitting pressure fluid to cause the piston to reciprocate within said cylinder, a resilient cylinder head adapted to be pressed into the upper end of said larger bore portion to seal and close the same and means for retaining said resilient cylinder head within the larger bore portion of said cylinder.

5. A tool comprising a body having a cylinder, a piston in said cylinder having a lower end extending outwardly from said body and terminating in an end adapted to work on a surface, a resilient cylinder head adapted to be pressed into the upper end of said cylinder to seal and close the same and means for retaining said resilient cylinder head within said cylinder. Y

6. An elastic pressure fluid operated tool having a body, said body having a cylinder, la piston adapted to reciprocate in said cylinder, the said piston having one end extending from the lower portion of said cylinder, and a plastic cylinder head adapted to be pressed into the other end of said cylinder :and providing the sole means or closing and sealing said end of said cylinder and means for retaining said head within said other end of said `cylinder.

References Cited in the file of this patent 2,944,521 Knabe July 12, 196,0 

1. AN ELASTIC PRESSURE FLUID OPERATED PERCUSSIVE TOOL COMPRISING A BODY HAVING A PLURALITY OF CYLINDERS, EACH CYLINDER HAVING A BORE OF TWO DIAMETERS, A PISTON IN EACH OF SAID BORES HAVING AN UPPER PORTION FITTING THE LARGER PORTION OF SAID BORE AND LOWER PORTION FITTING THE SMALLER PORTION OF SAID BORE AND EXTENDING THERETHROUGH OUTWARDLY FROM SAID BODY AND TERMINATING IN AN END ADAPTED TO WORK ON A SURFACE, THE SAID BODY HAVING PASSAGES CONTROLLED BY SAID PISTON FOR ADMITTING AND EXHAUSTING PRESSURE FLUID TO CAUSE THE PISTONS TO RECIPROCATE WITHIN SAID CYLINDERS, A SYNTHETIC RUBBER CYLINDER HEAD IN THE UPPER END OF EACH OF SAID LARGER BORE PORTIONS TO SEAL THE SAME, EACH OF SAID RESILIENT CYLINDER HEADS HAVING A HOLE TRANSVERSELY THERETHROUGH, THE SAID BODY HAVING HOLES THERETHROUGH REGISTERING WITH SAID CYLINDER HEAD HOLES, A SINGLE PIN EXTENDING THROUGH SAID HOLES IN SAID BODY AND CYLINDER HEADS, THE SAID PIN HAVING A DIAMETER LARGER THAN THE DIAMETER OF SAID CYLINDER HEAD HOLES. 